Description

Unfortunately, this means that isinstance(d, datetime.datetime) in django.utils.timesince will return False while the monkey-patch is in effect even though d is a real datetime.datetime.

The humanize tests rely on a fixed value: now = datetime.datetime(2012, 3, 9) which happens to be at 0h00. They pass by accident, really. Add an hour and a minute to now — this shouldn't matter at all — and they'll fail!

This is preventing me from writing correct tests for #18504, because datetime objects are treated as date objects and their time part is ignored. It's impossible to write tests for edge cases around DST changes with this bug.